1. Field of the Invention
The invention disclosed herein relates generally to fluid dispensing systems, and more particularly to a fluid dispensing system for controlling the mixing of a first fluid (i.e., a diluent such as water) with a second fluid comprising a food concentrate (e.g., sauces), a non-carbonated beverage concentrate (e.g., juice or isotonic drink concentrate), or a non-food concentrate (e.g., solvents such as windshield wiper fluids or cleaning fluids) and the like, at a mixing point within the fluid dispensing system. The system comprises a valve positioned in the dispensing system along the line of supply of the second fluid upstream of the mixing point, such valve being simultaneously actuated through application of positive and/or negative pressure to allow the second fluid to flow through the valve. Such positive and/or negative pressure is generated from the first fluid to be dispensed by the system and mixed with the second, such that the termination of flow of the first fluid immediately terminates flow of the second fluid to ensure precise mixing of the two fluids in the final solution and to prevent inadvertent leakage of the second fluid.
2. Description of the Background
Fluid dispensers have long been used in numerous food service locales, including retail restaurants, juice bars, hospitals, nursing homes, schools, and the like. Such fluid dispensers often require the mixing of diluents, such as, water and a flavoring agent (such as a soft drink flavoring syrup or juice, dairy, or isotonic concentrate), into a final product having a precise water to concentrate ratio to provide the consumer with the desired taste of the final product. In order to maximize the appeal of the product to the consumer, and thus obtain continuous customers and sales, it is critical that the ratio of water to concentrate be maintained at a precise level and mixed thoroughly, and that the system maintain a FDA prescribed level of sterility.
In the case of traditional dispensing systems, when dispensing soft drinks, the flavoring agent ordinarily comprises a generally tacky syrup of relatively low viscosity. However, when dispensing noncarbonated drinks, such as juices, dairy beverages, and isotonic drinks, the flavoring agent ordinarily comprises a concentrate which comprises a highly viscous fluid that presents greater difficulty in flow regulation than traditional flavoring syrups. Positive displacement pumps, such as peristaltic pumps, are often used to regulate the flow of such beverage concentrate dispensing systems. However, systems using pumps require that a large physical space be devoted to housing the pumping apparatus. Further, such systems are prone to leaking or clogging after repeated daily use. Moreover, commercial grade, less expensive pumps used in dispensing peristaltic pumps have also been found to provide imprecise dispensing of small volumes of liquid as would be dispensed, for example, for a 12 oz. juice drink. Moreover, such fixed ratio pumps tend to pass a xe2x80x9cslugxe2x80x9d of water or other driving fluid at the reversal on each half cycle of the pump, resulting in stratification or non-uniformity of the dispensed beverage. Such pumps are also prone to dispensing a bit of afterflow concentrate as the pump terminates operation at the end of the dispensing cycle, thus either inadvertently dispensing a slug of pure concentrate into the drink at the end of the cycle, or positioning a slug of pure, unmixed concentrate to be delivered to the cup prior to the water/concentrate mixture at the start of the next dispensing cycle, in turn dispensing beverages of highly variable quality. The existing juice dispensers using peristaltic pumps are not a self-flushing system and require disassembly to be cleaned.
Even outside the field of beverage dispensing systems, the problems mentioned above plague dispensing systems that attempt to dispense measure quantities of any fluid comprised of a viscous concentrate and a diluent, such as cleaning or other industrial fluids.
Thus, there is a need in the art for a fluid dispensing system which is capable of thoroughly and precisely mixing and dispensing fluids formed from a concentrate and a diluent, such fluids being of uniform ratio even for small volumes of dispensed fluids, which system avoids the problems associated with traditional fluid dispensing systems that utilize positive displacement pumps, which is more compact than traditional fluid dispensing systems, and which is effective in operation despite the inherent characteristics and anomalies of viscous concentrates. There is also a need for a system that offers a self-cleaning rinse mechanism after each use to insure the fluids are kept commercially sterile.
It is, therefore, an object of the present invention to provide a fluid dispensing system which avoids the disadvantages of the prior art.
It is another object of the present invention to provide a fluid dispensing system which can provide a uniform ratio of diluent to concentrate for each dispensed dose and maintain commercial sterility levels through a self-cleaning process. Either hot water and/or hot water in conjunction with an FDA approved hydrogen peroxide solution can be automatically attached to flush the lines of the system.
It is yet another object of the present invention to provide a fluid dispensing system which is actuated to dispense a first fluid via pressure applied by a second dispensed fluid.
It is still yet another object of the present invention to provide a fluid dispensing system having a dual-mode, system fluid actuated flow valve which is simultaneously and selectively actuated through the application of both positive and negative pressure forces in a complimentary fashion.
It is even yet another object of the present invention to provide a fluid dispensing system which immediately terminates the flow of concentrate upon the termination of flow of diluent so as to prevent the dispensing of an afterflow slug of concentrate at the end of the dispensing cycle or leakage of flavoring concentrate into the dispensing flow line or to allow bacteria to migrate back into the concentrate package.
It is even yet another object of the present invention to provide a fluid dispensing system which provides a dispensed fluid that is thoroughly and precisely mixed and blended even in small batches.
It is still even yet another object of the present invention to provide a fluid dispensing system which ensures the maintenance of a sterile environment for all non-dispensed portions of concentrate.
In accordance with the above objects, a fluid dispensing system is disclosed which enables the consistent, uniform dispensing and mixing of a desired ratio of concentrate to diluent, even for small volumes of dispensed fluids. The system of the present invention includes a valve positioned between the source of the concentrate and the point at which the concentrate is introduced to the diluent, the valve comprising a valve body having a first chamber, hereafter indicated as the xe2x80x9cflow chamber,xe2x80x9d and a second chamber, hereafter indicated as the xe2x80x9cactuation chamber,xe2x80x9d the flow chamber and the actuation chamber being separated by an intermediate wall within the valve body, and a plunger configured for reciprocal movement within the flow chamber and actuation chamber. A first end of the plunger comprises a valve head configured to seat against a valve seat wall in the flow chamber. When seated against the valve seat wall, the valve head prevents the flow of fluid through the flow chamber from a fluid inlet positioned on a first side of the valve head to a fluid outlet positioned on the opposite side of the valve head. A second end of the plunger comprises a piston head which is resiliently biased towards an end wall of the actuation chamber by a resilient member, and which in turn resiliently biases the valve head against the valve seat in the flow chamber. A flexible diaphragm is positioned between the piston head and the end wall of the actuation chamber, and separates the actuation chamber into a positive pressure actuation zone (the space between the diaphragm and the end wall of the actuation chamber) and a negative pressure actuation zone (the space between the diaphragm and the intermediate wall of the valve body). The end wall of the actuation chamber is provided with two ports, namely, a fluid inlet and outlet port for supplying fluid to and removing fluid from the positive pressure actuation zone. Likewise, the side wall of the actuation chamber is provided with one port, namely, a vacuum port for supplying a vacuum to the negative pressure actuation zone.
In operation, fluid applied to the inlet port of the positive pressure actuation zone, as well as vacuum applied to the vacuum port of the negative pressure actuation zone, each tend to compress the piston head against the resilient member, in turn moving the valve head in the flow chamber away from the valve seat to enable flow through the flow chamber.
The resilient member is so configured as to firmly hold the valve closed when diluent is not flowing, thus preventing the inadvertent leakage of concentrate into the flow system downstream of the valve. By closing the valve at the instant that diluent fluid flow is terminated, concentrate has no opportunity to leak into or come to rest within the flow system downstream of the valve, such that the entire volume of undispensed fluid is kept isolated from potential contaminants (e.g., bacteria) outside of the dispensing system.
In a preferred embodiment of the present invention, the valve is employed in a fluid control system for dispensing a first fluid that is to be mixed with a second fluid. In such embodiment, the first fluid to be dispensed (and mixed with the second) serves as both (1) the fluid applied to the positive pressure actuation zone, and (2) the fluid whose flow generates a vacuum to be applied to the negative pressure actuation zone, while the second fluid to be dispensed is that which flows through the flow chamber when the valve is actuated. In order to generate a vacuum to be applied to the negative pressure actuation zone of the valve, as well as to generate a vacuum to draw the second fluid (e.g., concentrate) from its storage vessel and into the stream of the first fluid (e.g., diluent), the fluid dispensing system of the present invention utilizes a venturi or ejector xe2x80x9cpumpxe2x80x9d to generate the required vacuum. In a preferred embodiment of the fluid dispensing system of the present invention, a diluent supply source is configured to simultaneously and selectively direct diluent (e.g., water) to the fluid inlet port of the positive pressure actuation zone of the valve, and through a venturi positioned downstream of the valve. The flow of diluent through the venturi generates vacuum forces which (i) draw the concentrate from its container when the valve is open; (ii) supply vacuum to the negative pressure actuation zone of the valve; and (iii) withdraw diluent supplied to the positive pressure actuation zone of the valve.